The gap between perceived mental health needs and actual service utilization in Australian adolescents

Despite being highly prevalent, adolescent mental health problems are undertreated. To better understand the mental health treatment gap, we assessed the prevalence and correlates of help-seeking, including perceived need for care and access to that care. Data were drawn from Young Minds Matter (YMM) survey—the second Australian child and adolescents survey of mental health and wellbeing. Parent-reported data and self-reported child data were combined into one dataset to analyse 2464 Australian adolescents aged 13–17 years. We employed bivariate and multivariate logistic regression models to assess the correlation between independent variables (professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both) and their distribution over outcome variables (perceived need and service use). Mental disorders include depression, anxiety, ADHD and conduct disorder. Our study revealed 15.0%, 4.6% and 7.7% had professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both, respectively. Overall, 47.4% and 27.5% of adolescents respectively perceived need for care and used services in the past-12-months. While among those only who perceived the need, only 53% of adolescents used any services. Professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both were associated with higher likelihood of perceived need and service use (p < 0.001 for all). However, adolescents who self-reported self-harm/suicidality only were not found to be significantly associated with service use among those who perceived the need for care. Adolescents who perceived the need for mental health care but did not seek care represent a treatment gap. Our results suggest the importance of reducing the wide treatment gap that exists between need and care.

. Briefly, YMM was a nationwide cross-sectional study that used a pilot tested Computer-Assisted Personal Interview (CAPI) questionnaire to conduct face-to-face interviews with parents in their homes. At the same time, a previously tested Computer-Assisted Self Interview (CASI) questionnaire was used for adolescents (11-17 years) to gather information related to health-risk behaviours privately at home 53,55 . A stratified, multistage, area-based random sample design (i.e., a child/adolescent was randomly selected if more than one child/adolescent was in the household) was employed. Overall, 6310 parents of children and adolescents aged 4-17 years (55% of eligible households) and 2967 adolescents aged 11-17 years (89% of eligible households) voluntarily participated in the survey between 2013 and 2014 53,54 . The interviews were conducted with representative samples of the nationwide resident population for the children and adolescents aged between 4 and 17 years in Australia. The overall response rate for the parents of children aged 4-17 years was 55%, while the percentage was 89% for the self-reported adolescents aged 11-17 years in Australia 3,53 . However, the YMM survey excluded children from remote regions, homeless children, children in any organisational care, and families where interviews could not be conducted in English 53,54 . Ethics. The Human Research Ethics Committees (HREC) of the University of Western Australia and the Australian Government Department of Health (Project 17/2012) approved the YMM research protocol. Later, to access the YMM datasets, our team obtained data access approval from the Australian Data Archive (ADA) Dataverse repository 52,53,55 . Further, the authorship team received ethical approval from the HREC of the University of Southern Queensland for using the YMM datasets to conduct research (HREC Approval No. H16REA205). Written informed consent was obtained for all YMM study participants (i.e., parents and for their children/ adolescents). All the investigations were carried out in accordance with appropriate ADA Dataverse guidelines and regulations in using the YMM datasets.
Measures. Prior studies 44,45 indicate predisposing factors (e.g. age, gender, education), enabling factors (e.g. geographic location, household income), and health outcome variables (e.g. illnesses, duration, severity) are commonly used to predict the perceived need for and service use among individuals with mental health problems. Thus, based on previous pertinent studies conducted among adolescents 11,26,36 , the variables listed in Table 1 were included in this study to achieve the study objectives.
Statistical analysis. The current study included 2464 adolescents aged 13-17 years of the nationally representative YMM survey. Figure 1 shows the flow chart of the final analytical sample. Respondents included in our study are those who have completed data on the outcome variables (perceived the need for mental health services and actual service use) and the three main explanatory variables (professionally assessed with mental disorders only-major depressive disorder, ADHD, anxiety and conduct disorder; self-reported self-harm and/or suicidality only; and the third group having reported both). The group making up "both" have at least one professionally diagnosed mental disorder and have self-reported self-harm or suicidality. This group is not counted in the other two groups. These variables were obtained from the merged parent-reported data and selfreported child data. During the analysis, the response categories 'Do not know' and 'Refused' , and 'Missing' were purposively omitted.
All data were weighted in accordance with the YMM survey's cluster sampling methodology, which employed strata and primary sampling units at the country level to ensure that the sample was nationally representative. Descriptive statistics were calculated first to describe sample population characteristics. Then, correlation matrix was estimated to see the strength and direction of relationships between selected variables. Further, Chi-square tests were employed to investigate the bivariate relationships between outcome variables (perceived need and service use) and main explanatory variables (mental health problems). Multivariate logistic regression models were constructed to examine the independent contributions of mental health problems, and sociodemographic covariates on perceived need and service use. Model estimates were reported as adjusted odds ratio (AOR) with 95% confidence interval (CI).
The logistic regression assumptions were evaluated using the McKelvey and Zavoina's R 2 56 and the Hosmer-Lemeshow Goodness-of-fit test 57 . Lastly, the variance inflation factor (VIF) test was used to find multicollinearity among the independent variables for each model 58 . We used 'SVYSET' command for survey design and used Stata software version 14.1 for analysis.

Results
Demographic characteristics. For this study sample of 13-17-year-olds (n = 2464), the mean age was 15.4 (SD = 1.38). More than half were (52%) boys, and nearly two-thirds were from major cities ( Table 2). The majority (80%) of adolescents attended school, and about 58% were living with their both biological parents. About 68% of adolescents were from families where at least one parent held a diploma and below education. Table 2 also shows more than three-quarters (76%) of adolescents lived in families where their parents were employed and greater than 75% of adolescents were from middle to high income families.  74 was used for both parents and self-reporting children (13-17 years) to get information about perceived need for care (i.e., information about services, medication, counselling, and life skills) for any diagnosed mental disorders and/or self-reported self-harm and/ or suicidality in the past 12 months prior to the survey. PNCQ is a reliable and validated tool, and previously used for the Australian National Survey of Mental Health and Wellbeing (for adolescents and adults) 4,74 . In this study, for the analytical purpose, we merged parentreported data and self-reported child data to create a dichotomous variable 'Perceived the need' from the Yes/No responses for each of the four categories of perceived need and finally, coded 1 for 'Yes' and 0 for 'No' 2 Service use Both parents (for their children) and children aged 13-17 years (self-reported) responded about whether the children accessed any of the following services in the previous 12 months-health services (includes general practitioners, psychiatrists, psychologists, community clinics, hospitals), school services, telephone counselling services and online services for any diagnosed mental disorders and/or self-reported self-harm/suicidality with the response options 'Yes' and 'No' for each category. In this study, during analysis, we merged parent-reported data and self-reported child data, created a binary variable 'Service use' for each child in the last 12-months from the Yes/No responses of each service category, and coded 1 for 'Yes' and 0 for 'No'

Main explanatory variable
3 Professionally assessed with mental disorders only In the YMM survey, initially, seven modules of the Diagnostic Interview Schedule for Children IV (DISC-IV) 75 were completed by parents for their children, and then, the responses were manually coded either by a qualified psychologist or psychiatrist on the YMM survey team to assess mental disorder/s in children in the past 12-months prior to survey using a structured interview questionnaire. The included mental disorders were major depressive disorder, attention-deficit-hyperactivity-disorder (ADHD), anxiety disorder and conduct disorder 3 . The responses for each mental disorder included 'Yes' and 'No' . In this study, for analytical purposes, we created a new dichotomous variable 'Professionally assessed with mental disorders only' in the past 12-months from Yes/No responses of each mental disorder. We coded 1 for 'Yes' when an adolescent was professionally assessed as having at least one of the four mental disorders only and did not self-report self-harm/suicidality 4 Self-reported self-harm/suicidality only In this study, for the analytical purpose, we created a new binary variable 'Self-reported self-harm/suicidality only' in the previous 12-months from Yes/No responses of the following self-reported variables: 'self-harm' and 'suicidality' . We coded 1 for 'Yes' when an adolescent self-reported either self-harm/suicidality only and was not professionally assessed as having any mental disorders Self-harm and Suicidality-In the survey, 12-17-year-olds children were directly asked about the experience of self-harm and suicidality in the last 12-months, where all the responses were kept private and not shared with consenting parents. Items measuring self-harm and suicidality were obtained from the validated and tested Standard High School questionnaire of the Youth Risk Behaviour Survey 76 . The following questions measured self-harm and suicidality, respectively: "Have you ever deliberately done something to yourself to cause harm or injury, without intending to end your own life?" and "During the past 12 months, did you ever seriously consider attempting suicide?" 3,53 . All responses were coded 1 for 'Yes' and 0 for 'No'

Both
During analysis, from Yes/No responses of 'Professionally assessed with mental disorders only' and 'Self-reported self-harm/suicidality only' respectively, we created a new variable 'Both' , for those who were assessed with at least one of the mental disorders and self-reported self-harm/suicidality (coded 1 for 'Yes' and 0 for 'No')

Neither
During analysis, from Yes/No responses of ' Assessed with mental disorders only' and 'Selfreported self-harm/suicidality only' respectively, we created a new variable 'Neither' , for those who neither assessed with any mental disorders nor self-reported self-harm/suicidality (coded 1 for 'Yes' and 0 for 'No')

Age
Age of the children was categorized into two groups: ' > 15 to ≤ 17' (coded as 1) and '13 to ≤ 15' (coded as 0) 8 Gender Gender of the children was categorized for both sexes: 'Girls' (coded as 1) and 'Boys' (coded as 0) 9 Country of birth Country of birth was categorized into ' Australian' (coded as 1), and 'Overseas' (coded as 0) 10 Place of residence According to the Australian Bureau of Statistics (ABS) from the Census of Population and Housing 2016 77 , remoteness areas divide Australia into 5 categories of remoteness based on relative availability of services-major cities, inner regional, outer regional, remote, and very remote. In this study, we created a binary variable 'Place of residence' from the responses. 'Major cities' was coded as '1' , while 'inner regional' , 'outer regional' , 'remote' and 'very remote' were combined to classify as 'regional/remote' (coded as 0) www.nature.com/scientificreports/ Prevalence of mental health problems. Figure 2 shows 15.0% (n = 370) of the total sample were professionally assessed with mental disorders only (i.e., any of the following disorders-major depressive disorder, ADHD, anxiety disorder or conduct disorder in the past 12-months). While 4.6% (n = 114) of adolescents selfreported self-harm and/or suicidality only in the previous 12-months. Figure 2 also shows around 7.7% (n = 190) of the sample had reported both, and 72.7% (n = 1790) neither assessed with mental disorders nor self-reported self-harm/suicidality.
Correlations among study variables. Table 3 portrays the matrix of correlation among the selected study variables. According to the table, mental health problems (professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both) are significantly associated with perceived need for and mental health service use. Perceived need was also linked with service use at 5% significance level. In addition, sociodemographic covariates such as age, gender, country of birth, family type and parental employment were associated with the outcome variables (perceived need for and service use itself), while family functioning and household income was inversely correlated with outcome variables. As expected, among the covariates, parental education, parental employment, and household income were found to be interlinked. Schooling of the adolescents and parental education was also connected.
Associations of mental health problems with perceived need and service use.  www.nature.com/scientificreports/ used mental health services; while the percentage of using services was around 4% for those who did not perceive the need for mental health problems. The bivariate analysis in Table 4 shows that about 77.1, 78.1 and 95.8% of adolescents who were professionally assessed as having mental disorders only, who self-reported self-harm/suicidality only and who reported both, respectively, perceived the need for care in the previous 12-months (p < 0.001 for all). In addition, those professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both were found to be associated with any service use in the past 12-months at a 1% significance level. Table 4 also illustrates that among those who perceived the need, approximately 70% (p < 0.001), 49% (p = 0.458) and 71% (p < 0.001) with professionally assessed mental disorders only, self-reported self-harm/suicidality only and both used any services in the past 12-months, respectively. That means a significant proportion of adolescents perceived the need but did not use any mental health services in the last 12-months, indicating a treatment gap. Surprisingly, among those adolescents who did not perceive the need, self-reported self-harm/suicidality only was found to be significantly associated with service use (p < 0.01).
Odds of perceived need and service use. The results of the logistic regression models that investigated the association of mental health problems (professionally assessed with mental disorders only, self-reported self-harm/suicidality only and both) with perceived need and service use among adolescents aged 13-17 are summarized in Table 5. All models were adjusted for potential sociodemographic covariates.
Model I in Table 5 shows that adolescents who were professionally assessed with mental disorders only, selfreported self-harm/suicidality only and had reported both were respectively 6   In addition, the findings revealed that girls, those who were born in Australia, those not living with their biological parents and having parents who have completed bachelor or above education were more likely to perceive the need (Model I) and use services (Model II, except for parental education) for mental health care compared to their counterparts (p < 0.05 for all). Model I also found that older adolescents (15-17 years) were more likely to perceive the need for care in comparison to younger aged adolescents. Model II found adolescents with unemployed parents were more likely to use services than those from employed parents. While in Model III, only gender and country of birth were found to be associated with service use among those who perceived the need for care compared to their counterparts (p < 0.05 for all). In addition, family type and parental employment were found to be significantly associated with service use among those who did not perceive need for mental health problems in Model IV (p < 0.05) in Table 5.
Model performance results. Lastly, Table 5 depicts the results of several statistical diagnostic tests used to verify the precision of estimates arising from the regression models. For instance, McKelvey and Zavoina R 2 values were smaller than one, and the Hosmer-Lemeshow Goodness-of-fit tests reveal no significant discrepancy between the models and the observed data (p > 0.05), indicating that the models were well-fitted. Additionally, the VIF with a mean of 1.20 for each model suggested no indication of multicollinearity among predictor variables.

Discussion
This study expands our understanding from previous research by providing further evidence on the perceived need for and mental health service use for 13-17-year-olds adolescents who had mental health problems in the past 12-months; using definition approach recommended by WHO (i.e., professionally assessed with mental disorders only-depression, anxiety, ADHD, conduct disorder; self-reported self-harm/suicidality only; and both). Our study used data from the latest nationally representative, mental health survey among children and adolescents in Australia-Young Minds Matter 53 . The findings of our study substantiated and extended beyond those from previous studies conducted in Australia by Schnyder et al. 4 and Johnson et al. 26 . In particular, our findings demonstrate that adolescents who were professionally assessed with mental disorders only, self-reported self-harm/suicidality only or reported both were significantly more likely to perceive the need for care and engage in actual service use. Importantly and uniquely, our research has also found that a significant proportion of adolescents who perceived the need for care were not using mental health services, and self-reported self-harm/ suicidality only was significantly associated with service use among those adolescents who responded that they did not perceive the need for mental health services.
Our study revealed that almost half of the sample (47.4%) perceived the need for care, which was consistent to that reported by Schnyder et al. 4 and Johnson et al. 26 . An earlier study carried out among adults in multiple developed countries also reported similar prevalence, primarily determined by psychiatric morbidity 44 . Further, we observed in our analyses that only around a quarter of the sample (27.5%) used any mental health services, which is relatively low compared to past studies, where previous study estimates vary between 30 and 40% 46,59 .
Furthermore, our study found the adolescents who were professionally assessed with mental disorders only and reported both a professionally assessed mental health condition and self-harm/suicidality were more likely to perceive the need for and seek mental health services than those who had not been professionally assessed with www.nature.com/scientificreports/ any disorder. Adolescents who experience significant burden associated with a mental disorder (e.g., inattention, worrying, sadness, social isolation, interruption in work, lower educational achievement, financial burden, reduced quality of life) 60-62 , may motivate individuals to seek mental health services to help their diagnosis in order to improve the poor mental health conditions. In addition, our study revealed that adolescents who selfreported self-harm and/or suicidality only were more likely to perceive the need for care and seek mental health services (statistically significant but low in effect compared to perceived need). While self-reported self-harm/ suicidality only was not significantly associated with service use among those who perceived the need for these services. Possible barriers to accessing services among those who perceive the need to seek these services commonly include worries about being stigmatized, fear of embarrassment, lack of knowledge and understanding of the help-seeking process and importantly, a desire to solve problems on their own without involving others (eg. parents) 62,63 . Interestingly, our study found that self-reported self-harm/suicidality only was associated with higher likelihood of using services among those adolescents who did not perceive the need for care. This may be because adolescents did not perceive the need for care earlier and potentially accessed the available service on an emergency basis only after a crisis incident (self-harm/suicidality). Previous studies have found that adolescents with self-harming/suicidal behaviour are more likely to seek help from peers, counsellors and health professionals but are less likely to seek help from parents, siblings or relatives 64,65 . Further, our study highlights a significant disparity between the perceived need for mental health services and actual service use. Overall, about half of the adolescents (47%) did not seek mental health services although they perceived the need for care. This gap is consistent with earlier studies, where contextual factors and family influences (parents not realising their adolescent needs help) were reported as key 65,66 . This conflict between Table 5. Logistic regression models predicting perceived need and service use. Level of significance: ***p < 0.001, **p < 0.01, *p < 0.05. aOR Adjusted odds ratio, CI Confidence interval; VIF Variance inflation factor.  36 . Based on our findings and earlier evidence, this suggests that the parent plays a major role in deciding whether their adolescent accesses mental health services and parents act on what they observe, know about, or feel is important, but the observations made by the parent may not adequately reflect how the adolescent is doing in terms of their mental well-being. This knowledge highlights areas for improvement. Improvements might include assisting parent-adolescent communication of mental health needs, further bolstering services and processes that enable adolescents to seek care independent of the parent, education for parents regarding the range of mental health needs and what health services can do to help. Continuing improvements in mental health services for adolescents might consider that Australian adolescents with self-harm/suicidality are more likely to use online and in-person health services such as GP, psychologists, paediatricians, hospitals, private clinics, emergency departments and counsellors/family therapists and are less likely to use telephone services 27,35,36 . Moreover, our study found that adolescents born overseas were less likely to perceive need for mental health care and seek services compared to those who were born in Australia. This may be due to cultural barriers in terms of perceived social stigma regarding mental health conditions, embarrassment and mental health illiteracy 63,67,68 . Prior studies have shown that girls are more likely to seek mental health services and are more likely to perceive the need for services than boys 45 ; our study supports this statement. Additionally, our study found adolescents who live with blended/stepparents were more likely to perceive need and use mental health services, which is consistent with the findings from a previous study that reported family circumstances are significantly associated with perceived mental health needs and service access 69 . Furthermore, the findings of our study suggested that highly educated parents increase the likelihood of perceived need for care among adolescents. This may be because parents with higher education have better knowledge of mental health problems than parents with comparatively lower educational level 63 . In addition, our study estimated that 23.5% of parents were unemployed, this is because mother was primarily included as the parent and/or caregiver by the YMM survey. Latest reports on labour force status of families by the Australian Bureau of Statistics estimated that 74% of mothers with adolescents in couple families are employed 70 .
Using the latest national representative survey data is one of the major strengths of our study since it has previously been concluded that the YMM survey broadly represents the Australian adolescent population on major demographic characteristics 53 . Further, the YMM survey included professionally assessed mental disorders and standardised items for self-reported mental health conditions (self-harm/suicidality) for children and adolescents as described by the World Health Organization (WHO) 7 . In addition, having merged report (parent-reported data and self-reported data) on perceived need and service use is a strength of the study. However, our study has several limitations. First, the cross-sectional nature of the YMM survey, limits our ability to understand temporal causality between explanatory and outcome variables. Second, the YMM survey was conducted only among non-Indigenous 4-17 years adolescents in Australia; thus, the results may not be generalized for Australian adults and Indigenous adolescents. Third, information regarding self-harm and suicidality were self-reported and hence, measurement error and recall and/or response bias may be affecting the data 71 . Although previous studies validated self-reporting as the most plausible method for health risk behaviours among children and adolescents 72,73 . Fourth, important variables such as substance use disorder, eating disorder and post-traumatic stress disorder were not available in the YMM survey dataset, this limits the findings of the study. Lastly, the survey lacked an evaluation of whether the service use improved adolescents' mental health, their school performance or social functioning.

Conclusions
This study found that a significant proportion of adolescents who perceived the need for care did not use mental health services and this was particularly stark for adolescent's experiencing self-harm and/or suicidality. The mental health needs of adolescents were already high in Australia and globally, and COVID-19 has exacerbated this. While funds are being dedicated to increase mental health services in Australia, it will be crucial to act on findings such as those in this paper, which demonstrate a wide treatment gap exists for adolescents with mental health needs who do not seek care.